1. Field of the Invention
The present invention relates to a bearing device and a swing arm assembly for a magnetic disk, in which resonance frequency can be finely adjusted.
2. Description of the Related Art
In some kinds of bearings, resonance frequency can be adjusted. For example, Japanese Patent Application, First Publication No. 2002-327765, discloses a bearing unit which is press-inserted between a shaft and a sleeve and is fixed thereto while measuring axial resonance frequency, whereby axial frequency may be adjusted to a predetermined value.
Japanese Patent Application, First Publication No. 2002-157848, discloses a bearing structure for supporting an arm for a magnetic disc in which a stepped portion is provided on an outer surface of a housing of a bearing unit or on an inner surface of the arm. In the structure, the stepped portion is provided for separating the bearing device from the arm, whereby external force exerted to a bearing and change of torque are reduced, thereby reducing torque.